From svakil at gmail.com  Mon Oct 22 16:13:42 2007
From: svakil at gmail.com (Sanjay Vakil)
Date: Mon, 22 Oct 2007 16:13:42 -0400
Subject: [TZInfo-users] more generic names?
Message-ID: <b705ada10710221313m13c4aa43qfc3a1e77992adcee@mail.gmail.com>

Hiya!

TZInfo is back in my life, and that's quite nice.

What I'd like to do is to show the "simpler" names of timezones,
rather than the city name:

EST instead of America/New_York
PST instead of America/Los_Angeles

Is there a way to derive this?

I looked at linked_zones, thinking I could use those, but they don't
appear to link back to the country in question, or the zone that they
link to.

At minimum, from a UI standpoint, it'd be nice to show something like:

EST - New York

Thanks,
Sanjay

-- 
The world tends to work out for me.  I try to give it reason to.

From svakil at gmail.com  Mon Oct 22 16:17:52 2007
From: svakil at gmail.com (Sanjay Vakil)
Date: Mon, 22 Oct 2007 16:17:52 -0400
Subject: [TZInfo-users] population numbers?
Message-ID: <b705ada10710221317s1f30b84s7b69ec2361c8e7b4@mail.gmail.com>

Hiya.

In the docs, it talks about a given country's list of TZs being
organized geographically, and then by population.

Is the population data available?  Could it be made so?

Here's why:

I'm using javascript to get a UTC offset.  And then using that offset,
along with the country that the user's selected, to attempted to guess
at the correct timezone.  The code only has one axis to work on -- how
close the offset is.

As such, it automatically grabs the very first entry that matches.  In
the case of Canada, a GMT-4 shows us as "Blanc-Sablon" rather than,
say, Montreal or Toronto.  If the population data were to be
available, I'd use that to sort all of the matches and choose the most
populous one.

Thanks,
sanjay

-- 
The world tends to work out for me.  I try to give it reason to.

From svakil at gmail.com  Mon Oct 22 16:20:50 2007
From: svakil at gmail.com (Sanjay Vakil)
Date: Mon, 22 Oct 2007 16:20:50 -0400
Subject: [TZInfo-users] one more...
Message-ID: <b705ada10710221320p220f52a0tfd07c3c13957c012@mail.gmail.com>

It appears, in looking at the zone data, that there are multiple
"city" entries in what much of the world considers a single timezone.

I'm assuming this is for historical reasons -- Detroit and New York
were not always in the same timezone.

Is there a way to get a list of just those timezones which are
actually different going forward?

I guess this relates back to my earlier question about showing PST/EST/MST/CST.

sanj

-- 
The world tends to work out for me.  I try to give it reason to.

From phil.ross at gmail.com  Mon Oct 22 18:15:56 2007
From: phil.ross at gmail.com (Philip Ross)
Date: Mon, 22 Oct 2007 23:15:56 +0100
Subject: [TZInfo-users] more generic names?
In-Reply-To: <b705ada10710221313m13c4aa43qfc3a1e77992adcee@mail.gmail.com>
References: <b705ada10710221313m13c4aa43qfc3a1e77992adcee@mail.gmail.com>
Message-ID: <4ac540410710221515o5cd2eb37u6ea6e3b377ec1f87@mail.gmail.com>

On 22/10/2007, Sanjay Vakil <svakil at gmail.com> wrote:
> What I'd like to do is to show the "simpler" names of timezones,
> rather than the city name:
>
> EST instead of America/New_York
> PST instead of America/Los_Angeles
>
> Is there a way to derive this?
>
> I looked at linked_zones, thinking I could use those, but they don't
> appear to link back to the country in question, or the zone that they
> link to.

Linked timezones are just aliases to other zones. TZInfo hides the
details of the linked timezone.

There is no link from a timezone to the country or countries that use
it. You could use the information available through the Country class
to build such an index though.

> At minimum, from a UI standpoint, it'd be nice to show something like:
>
> EST - New York

If you are interested in seeing EST/EDT, etc, then you can obtain a
TimezonePeriod object using Timezone#current_period,
Timezone#period_for_utc or Timezone#period_for_local and call its
abbreviation method.

The New York part can be obtained by calling Timezone#friendly_identifier(true)

Phil

-- 
Phil Ross
http://tzinfo.rubyforge.org/ -- DST-aware timezone library for Ruby

From phil.ross at gmail.com  Mon Oct 22 18:16:34 2007
From: phil.ross at gmail.com (Philip Ross)
Date: Mon, 22 Oct 2007 23:16:34 +0100
Subject: [TZInfo-users] population numbers?
In-Reply-To: <b705ada10710221317s1f30b84s7b69ec2361c8e7b4@mail.gmail.com>
References: <b705ada10710221317s1f30b84s7b69ec2361c8e7b4@mail.gmail.com>
Message-ID: <4ac540410710221516o42675410yecb00ffa2c4d43df@mail.gmail.com>

On 22/10/2007, Sanjay Vakil <svakil at gmail.com> wrote:
> Hiya.
>
> In the docs, it talks about a given country's list of TZs being
> organized geographically, and then by population.
>
> Is the population data available?  Could it be made so?

TZInfo uses data from the tz database
(http://www.twinsun.com/tz/tz-link.htm) and this is where that
statement is taken from.

I don't have the population data. It isn't available in machine
readable format in the tz database. You could try asking on the tz
mailing list (referenced in the link above) to see if anyone has done
anything involving population data and timezones before.

> Here's why:
>
> I'm using javascript to get a UTC offset.  And then using that offset,
> along with the country that the user's selected, to attempted to guess
> at the correct timezone.  The code only has one axis to work on -- how
> close the offset is.

Other people I've spoken to about doing similar things have tended to
go for a bit of manual tweaking to pick representative zones for the
larger countries.

Phil

-- 
Phil Ross
http://tzinfo.rubyforge.org/ -- DST-aware timezone library for Ruby

From phil.ross at gmail.com  Mon Oct 22 18:17:46 2007
From: phil.ross at gmail.com (Philip Ross)
Date: Mon, 22 Oct 2007 23:17:46 +0100
Subject: [TZInfo-users] one more...
In-Reply-To: <b705ada10710221320p220f52a0tfd07c3c13957c012@mail.gmail.com>
References: <b705ada10710221320p220f52a0tfd07c3c13957c012@mail.gmail.com>
Message-ID: <4ac540410710221517p6ce9b9bfp753421d9f2a09@mail.gmail.com>

On 22/10/2007, Sanjay Vakil <svakil at gmail.com> wrote:
> It appears, in looking at the zone data, that there are multiple
> "city" entries in what much of the world considers a single timezone.
>
> I'm assuming this is for historical reasons -- Detroit and New York
> were not always in the same timezone.

Yes, your assumption is correct. Detroit and New York have been
different in the past, but since 27 April 1975 have used identical
rules.

The source tz database (http://www.twinsun.com/tz/tz-link.htm) lists
all the timezones available for each country rather than just those
with different current and future rules.

> Is there a way to get a list of just those timezones which are
> actually different going forward?

There isn't a simple way to do this with TZInfo - you'd have to
compare each future TimezonePeriod for each pair of Timezones to
determine if they were the same. If they were the same, you'd need a
rule of some sort to determine which zone you will use, so this might
require some manual intervention.

> I guess this relates back to my earlier question about showing PST/EST/MST/CST.

For the US, there are a set of linked timezones defining the distinct
set of rules that are in force. These are:

US\Alaska
US\Aleutian
US\Arizona
US\Central
US\East - Indiana
US\Eastern
US\Hawaii
US\Indiana - Starke
US\Michigan
US\Mountain
US\Pacific
US\Samoa

Phil

-- 
Phil Ross
http://tzinfo.rubyforge.org/ -- DST-aware timezone library for Ruby

From svakil at gmail.com  Mon Oct 22 20:03:06 2007
From: svakil at gmail.com (Sanjay Vakil)
Date: Mon, 22 Oct 2007 20:03:06 -0400
Subject: [TZInfo-users] more generic names?
In-Reply-To: <4ac540410710221515o5cd2eb37u6ea6e3b377ec1f87@mail.gmail.com>
References: <b705ada10710221313m13c4aa43qfc3a1e77992adcee@mail.gmail.com>
	<4ac540410710221515o5cd2eb37u6ea6e3b377ec1f87@mail.gmail.com>
Message-ID: <b705ada10710221703u4d8522bq78780886e22c54c1@mail.gmail.com>

> There is no link from a timezone to the country or countries that use
> it. You could use the information available through the Country class
> to build such an index though.

This is the bit I couldn't figure out.  Could you elucidate?

thanks,
sanj


On 10/22/07, Philip Ross <phil.ross at gmail.com> wrote:
> On 22/10/2007, Sanjay Vakil <svakil at gmail.com> wrote:
> > What I'd like to do is to show the "simpler" names of timezones,
> > rather than the city name:
> >
> > EST instead of America/New_York
> > PST instead of America/Los_Angeles
> >
> > Is there a way to derive this?
> >
> > I looked at linked_zones, thinking I could use those, but they don't
> > appear to link back to the country in question, or the zone that they
> > link to.
>
> Linked timezones are just aliases to other zones. TZInfo hides the
> details of the linked timezone.
>
> There is no link from a timezone to the country or countries that use
> it. You could use the information available through the Country class
> to build such an index though.
>
> > At minimum, from a UI standpoint, it'd be nice to show something like:
> >
> > EST - New York
>
> If you are interested in seeing EST/EDT, etc, then you can obtain a
> TimezonePeriod object using Timezone#current_period,
> Timezone#period_for_utc or Timezone#period_for_local and call its
> abbreviation method.
>
> The New York part can be obtained by calling Timezone#friendly_identifier(true)
>
> Phil
>
> --
> Phil Ross
> http://tzinfo.rubyforge.org/ -- DST-aware timezone library for Ruby
> _______________________________________________
> TZInfo-users mailing list
> TZInfo-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/tzinfo-users
>


-- 
The world tends to work out for me.  I try to give it reason to.

From phil.ross at gmail.com  Tue Oct 23 05:32:00 2007
From: phil.ross at gmail.com (Philip Ross)
Date: Tue, 23 Oct 2007 10:32:00 +0100
Subject: [TZInfo-users] more generic names?
In-Reply-To: <b705ada10710221703u4d8522bq78780886e22c54c1@mail.gmail.com>
References: <b705ada10710221313m13c4aa43qfc3a1e77992adcee@mail.gmail.com>
	<4ac540410710221515o5cd2eb37u6ea6e3b377ec1f87@mail.gmail.com>
	<b705ada10710221703u4d8522bq78780886e22c54c1@mail.gmail.com>
Message-ID: <4ac540410710230232lf149dbbt8b24862ecafd9b60@mail.gmail.com>

On 23/10/2007, Sanjay Vakil <svakil at gmail.com> wrote:
> > There is no link from a timezone to the country or countries that use
> > it. You could use the information available through the Country class
> > to build such an index though.
>
> This is the bit I couldn't figure out.  Could you elucidate?

The following code will give you a hash mapping timezone identifiers
to the country that uses that timezone.

TZInfo::Country.all.inject({}) do |zones,country|
  country.zone_identifiers.each {|zone_id| zones[zone_id] = country}
  zones
end

The hash won't contain every timezone - just those that are defined as
part of a country.

Phil

--
Phil Ross
http://tzinfo.rubyforge.org/ -- DST-aware timezone library for Ruby

From svakil at gmail.com  Tue Oct 23 07:44:53 2007
From: svakil at gmail.com (Sanjay Vakil)
Date: Tue, 23 Oct 2007 07:44:53 -0400
Subject: [TZInfo-users] more generic names?
In-Reply-To: <4ac540410710230232lf149dbbt8b24862ecafd9b60@mail.gmail.com>
References: <b705ada10710221313m13c4aa43qfc3a1e77992adcee@mail.gmail.com>
	<4ac540410710221515o5cd2eb37u6ea6e3b377ec1f87@mail.gmail.com>
	<b705ada10710221703u4d8522bq78780886e22c54c1@mail.gmail.com>
	<4ac540410710230232lf149dbbt8b24862ecafd9b60@mail.gmail.com>
Message-ID: <b705ada10710230444h6f3d4dddl4cd6b5bc85344899@mail.gmail.com>

I've (independently) written almost exactly that code!  I'm glad my
Ruby skills are finally getting there.

The problem is that each country only appears to contain a single
entry for each timezone.  What ends up missing is the US/Eastern
entries, which are redundant.

I suspect that I'll end up tweaking this by hand for the countries
that are wide enough to have many time zones.

Based on this:

(TZInfo::Country.all.map() { |c|[c.name, c.zones.size]}).delete_if {|z| z[1]<4}

Only about 13 countries have more than 4 timezones:

[["Indonesia", 4],
 ["China", 5],
 ["Mexico", 8],
 ["Ukraine", 4],
 ["Brazil", 15],
 ["Russia", 15],
 ["United States", 25],
 ["Kazakhstan", 5],
 ["Antarctica", 10],
 ["Argentina", 10],
 ["Greenland", 4],
 ["Australia", 11],
 ["Canada", 26]]

And, let's face it, only about 6 of those have >10 and are really an issue.

Thanks again!
Sanjay

On 10/23/07, Philip Ross <phil.ross at gmail.com> wrote:
> On 23/10/2007, Sanjay Vakil <svakil at gmail.com> wrote:
> > > There is no link from a timezone to the country or countries that use
> > > it. You could use the information available through the Country class
> > > to build such an index though.
> >
> > This is the bit I couldn't figure out.  Could you elucidate?
>
> The following code will give you a hash mapping timezone identifiers
> to the country that uses that timezone.
>
> TZInfo::Country.all.inject({}) do |zones,country|
>   country.zone_identifiers.each {|zone_id| zones[zone_id] = country}
>   zones
> end
>
> The hash won't contain every timezone - just those that are defined as
> part of a country.
>
> Phil
>
> --
> Phil Ross
> http://tzinfo.rubyforge.org/ -- DST-aware timezone library for Ruby
> _______________________________________________
> TZInfo-users mailing list
> TZInfo-users at rubyforge.org
> http://rubyforge.org/mailman/listinfo/tzinfo-users
>


-- 
The world tends to work out for me.  I try to give it reason to.